1. Technical Field
The system of the present invention relates to sandblasting. More particularly, the present invention relates to a novel system for dry or wet sandblasting providing continuous air lift support for the blasting stream of air, water and sand and having a minimum of pollutant material in the atmosphere during the sandblasting operation.
2. General Background
At the present time, there are numerous systems wherein sandblasting equipment is utilized to provide a blasting stream of air and sand yet undesireable dispersion of sand and dust from the object being cleaned into the atmosphere in the vicinity of the equipment. The various methods of mixing the water and sand include mixing inside of a nozzle to provide a blasting stream containing water in order to help prevent the dispersion of sand and the abrasive dust. A likewise problem that is also confronted in the art is in the sandblasting of structures such as high buildings or elevated railways. The sandblasting equipment must be placed adjacent to the area being sandblasted in view of the fact that the pressurized sand moving through the sandblasting line loses its pressurization as it continues down the line in order to achieve maximum sandblasting effects. There is an overall need for a system wherein low dispersion of sand and dust in the vicinity of the equipment being cleaned can be achieved, together with the ability to convey the pressurized sand and mixture of water and/or air to the point being sandblasted over a distance without losing the pressure behind the abrasive cleaner.
There are several patents which have been obtained addressing the problem of sandblasting equipment and the like, the most pertinent being as follows:
U.S. Pat. No. 3,271,903, issued to W. C. Gregory, entitled "Maintaining The Resistivity Of Insulating Members In Energized Electric Equipment," although addressing an invention for maintaining the resistivity of energized electric equipment in reducing the likelihood of injury from electrical shock, does disclose the use of a double tank system for adding fluids or the like to a flow such as compressed air for achieving sandblasting or the like.
U.S. Pat. No. 3,828,478, issued to E. G. Bemis entitled "Fluid-Jet-Abrasive Device And System," again teaches the use of a system for mixing fluids from a storage tank, a high presure water pump and an abrasive reservoir tank for mixing the components into a fluid flow line. Although there is addressed a mixing of the materials in the tool, there is no disclosure of a continuous feeding of compressed air or the like into the line for achieving the maximum flow as with the present invention.
U.S. Pat. No. 3,858,358, issued to J. E. Stachowiak, et al., entitled "High Pressure Liquid And Abrasive Cleaning Apparatus," provides a high velocity, high pressure blasting system that cleans an object without polluting the atmosphere. There is included a blasting gun having a blasting nozzle for directing outwardly therefrom a low velocity stream of air abrasive mixture and a high velocity stream of water. The control means for controlling the flow of liquid and gas abrasive mixture is provided.
U.S. Pat. No. 3,994,097, issued to R. W. Lamb, entitled "Abrasive Or Sand Blast Apparatus And Method," discloses a nozzle assembly formed from a housing which is a water nozzle positioned in the rear wall having an orifice designed to produce a gradually diverging water jet in the housing when pressurized water is added to it.
U.S. Pat. No. 3,769,753, issued to H. Fleischer entitled "Automatic Car Sand Blaster," was included in the search since it did relate to the pre-mixing of the materials just prior to release of the mixture by the gun. U.S. Pat. Nos. 3,972,150; 3,103,765; 3,584,481; 3,343,304; 4,330,968; and 4,319,435 are all systems directed toward pressure water sandblasting or slurry sandblasting, and although are part of the art, are not as pertinent as the previous art.